Ancient fossil finds in Namibia

SOUTHERN Namibia not only has interesting landscapes and wide open spaces, but bears hidden treasures millions of years old.

It was only 19 years ago that sheep farmer Giel Steenkamp on farm Spitzkoppe east of Keetmanshoop by chance found the fossilised remains of a forgotten creature on his land, reminding him of the film ‘Jurassic Park’, which started an international and continuing craze for dinosaurs.
‘When we brought a few examples of the rock formation with fossil traces to experts in Windhoek after our find, we were informed that they belonged to a smallish dinosaur called mesosaurus,’ Steenkamp told The Namibian during a visit to the fossil site last week.
‘Even more interesting, this mesosaurus is about 300 million years old and was found in eastern Brazil as well. This provides proof that the continents of Africa and South America once formed one continent, scientists told us,’ Steenkamp added.
‘Other mesosaurus finds were made in South Africa years earlier, but in Namibia, our farm is the best site as more of them were allegedly found along the Doros crater in north-western Namibia.’
Tourists have been appearing in larger numbers since Steenkamp, who handed over farming activities to his son, started advertising the site five years ago. His farm also boasts about 5 000 quiver trees, which are densely clustered near the fossil site.
According to Steenkamp, the mesosaurus is probably one of the most convincing examples to prove the theory of continental drift. The same genus in the same rock formations is found in both southern Africa and South America, located in shallow seas, in basins and river mouths.
Mesosaurus creatures were between 1 and 2 metres tall and had long bent teeth embedded in the jaws in a hinge-like fashion so that they could bend outwards from the jaw when it closed.
Mesosaurus had 31 vertebrae just before the tail. The mesosaurus was a peaceful and harmless species. It is believed to have been a filter feeder due to the structure of its teeth and fed on plankton, fish eggs and small larva.
Its feet were webbed, its body was streamlined, and its long tail supported a fin. Since the hind legs were much longer, they are presumed to have been used to propel the creature through water. Its body was flexible and could easily move sideways, but it could not turn as a result of highly thickened ribs, according to Wikipedia.
Due to the shape of the front feet the mesosaurus moved with great difficulty on land, but was a profound swimmer by using its tail and possibly webbed feet to propel it in the water.
Even small mesosaurus of 35 cm were found far from land. The biggest were about 2 metres long, making them the largest animals of their time. The fossils found so far on Spitzkoppe farm are of small mesosaurus up to 40 cm long.

FOOTPRINTS

Other traces of dinosaurs in Namibia are on the farm Otjihaenamaparero near Mount Etjo. Dinosaur tracks occur in sandstone of the 190-million-year old Etjo Formation on the way to Otjiwarongo.
As the climate became drier, these animals were forced to concentrate near waterholes, small lakes and rivers fed by occasional rainfalls and thunderstorms. Inevitably, their feet left imprints in the wet sediment around the water.
Later these imprints were covered by other layers of wind-blown sand, and were preserved as trace fossils when the sand solidified into rock due to the pressure that built up as they were buried deeper and deeper.
At Otjihaenamaparero, two crossing tracks consist of more than 30 imprints with a size of approximately 45 by 35 cm. The longer tracks can be followed for about 28 metres.
There is a distance of some 70 to 90 cm between individual imprints as well as some tracks comprising smaller imprints of about 7 cm long and spaced about 28 to 33 cm apart.
All tracks show the form of a three-toed, clawed foot very well, and from their arrangement it can be deducted that they were made by the hind feet of the animal.
Unfortunately, no body fossils of creatures that could have made the tracks have been found in the area so far.
Worldwide, about 900 dinosaur species are known through the finds of body fossils, but only a few dozen fossilised footprints have been discovered.
From these it can be concluded that the dinosaur that left the footprints at Otjihaenamaparero possibly belonged to the large order of ‘therapodia’.
The dimensions and the depth of the imprints suggest that the dinosaur had an appreciable size.
Due to the unfavourable changes in climate described above, it can be assumed that the animals became extinct not long after they left their footprints.
There are a number of localities in the Etjo Sandstone that contain dinosaur footprints, but Otjihaenamaparero is the most impressive one. The site has been declared a national monument, and the footprints are thus protected by law.